1. Field of the Invention
This invention relates to the field of intrusion detectors, and more particularly to an intrusion detector specifically applicable for use in passenger aircraft, wherein the detector is self-contained and portable, can be located centrally in the aircrafts and detects activity along a beam alignable with the aisle of the aircraft, thereby protecting the aircraft whether the exterior doors are opened or closed.
2. Prior Art
Various forms of intrusion detectors are known for use in buildings, and intrusion detectors are also known for detecting attempts to gain access to closed and locked vehicles. Typically, intrusion detectors for vehicles are powered by the on board vehicle power supply (e.g. battery) or are mounted as securely and non-portably as can be arranged, whereby attempts to remove and disable the detector are impeded. Frequently, intrusion detectors or their alarm condition signalling means are concealed such that an intruder will not be aware that he has been detected. One would logically conclude that it is not advisable to provide a truly portable intrusion detector for a typical vehicle, because it would be relatively easy for an intruder to remove the entire portable detector from the vehicle, and to drive away before an appropriate security response on the part of the vehicle owner. Therefore, typical prior art intruder detectors for vehicles are rather permanently affixed to the vehicle and are not portable. A typical vehicle-type intrusion sensor is disclosed in U.S. Pat. No. 4,218,763-Kelley, et al.
A portable self-contained intruder detector described as useful for vehicles is disclosed in U.S. Pat. No. 4,222,043-Malavasi. The patent teaches a grounding-sensitive device for use on equipment including cars, aircraft and other equipment. When external connections to the intruder detector are broken, or when the ground connection of the vehicle is broken, for example when the vehicle is moved, an alarm circuit including silicon controlled rectifiers (SCRs) latches on and can only be reset using a switch. The device of this patent is useful for detecting when the vehicle is moved, but has no particular structure associated with the detector that is useful for preventing surreptitious access to aircraft, buses, trains, cars and the like, in which an intruder does not move the vehicle but visits it briefly, for example in order to install a bomb or to conceal contraband.
Air transportation systems have been especially susceptible to attacks by terrorists and criminals because aircraft in transit are especially vulnerable. Many lives have been lost. Heretofore, protection against acts of sabotage, vandalism and the like and efforts to thwart smugglers have been accomplished through airport perimeter security rather than vehicle internal security, and through the personal attention of security personnel.
An aircraft may be stationed at a passenger loading gate for long periods of time (for example all night), when access to the aircraft itself is not restricted directly but access to the general gate area is restricted by metal detectors and security cordons manned by security personnel. Of course, there is always a danger that airport staff or even security personnel may choose or be forced to collaborate with terrorists or criminals, allowing access to an aircraft on the ground. Nonmetallic or camouflaged explosive device and contraband can be passed through detection equipment. Even the most aggressive security procedures can be circumvented by the defection of one individual among many on the maintenance and security staff. An individual with free access to aircraft within the perimeter of a security system, presents a danger.
The present invention limits the access of even security personnel to aircraft within a secure perimeter. The intrusion detector of the invention is portable and self-contained and therefore is free of exposure to tampering during maintenance of the aircraft or other vehicle. Inasmuch as the detector is portable, only a very limited number of persons need have access and knowledge of installation and code procedures. The detector is hand-carried onto the aircraft and activated by the security person having custody, and is therefore safe from tampering. The housing of the detectoro is adapted to be aligned to the aisle between the aircraft seats, and preferably detects intrusion anywhere along aligned detection beams. Should even a security person gain access to the aircraft, the detector is activated. However, a time delay is preferably built in prior to activation of audible and visible alarm indicators, permitting security personnel to disable the device via a key or code entry. A key or switch pad-entered code is needed for programming as well as to disable the detector and a plurality of security levels can be defined, only the highest levels being able to accomplish critical changes such as password definition. Access to special codes and keys can be severely limited without undue inconvenience in day-to-day use.
Mounted detection and signalling devices having means to engage portions of buildings, rather than an aircraft, are known wherein the devices define detection beams. Reference can be made, for example, to U.S. Pats. Nos. 4,446,454-Pyle or 4,412,211-Lautzenheiser et al., each of which includes a sensor defining a detection means and a signalling device. These devices are useful, but apply to detection applications which are not as critical as aircraft. The typical building security system can be permanently installed without as great a danger of loss if intruders tamper with the system during maintenance on the premises.
Portable personal security devices are known in some variation. Typically, portable devices have an audible alarm and/or flashing light alarm that is activated whenever the portable alarm device is disturbed. The user places the portable device against a door or the like and the alarm is activated when the door is opened and the device disturbed. For example, a resiliently biased contact switch located on the bottom of the housing can be released and activated when the unit is knocked over (U.S. Pat. No. 3,579,222-Freeman). A window, door or similar means can produce a contact sensed disruption for operating a switch (U.S. Pat. Nos. 4,438,428-Ober et al.; 4,264,892-Zonn; 4,191,947-Bouchard et al.; 3,710,371-Whalen et al.; or 3,430,219-Powers).
The present invention is specifically adapted to severely limit access to passenger aircraft. One or more passive infrared sensing beams are preferably provided for motion detection the beams being alignable to the aisle, for example by engaging one of the passenger seats with the housing of the device. Vibration (e.g., sound) and electromagnetic (e.g. capacitance) sensors can be included. A radio-signalling means alerts a remote monitoring device, for example a portable beeper or central monitoring station, and this signal can be generated prior to or concurrently with any audible or visual alarm. To allow the location of the intrusion to be determined immediately amonng a plurality of aircraft or the like, facilitating apprehension the intruder, a strobe light is preferably arranged to flash within the aircraft cabin. This or other light emitting means can be spaced from the detector housing and connected by a flexible conductor to the housing, which is to be located remote from vehicle exits. The effect of the device is not only alert security personnel to the occurrence of an intrusion, but the particular aircraft subject to the alarm becomes a huge flashing indicator among other aircraft as all the passenger windows reveal the flashing strobe signal emitted therein.
Strobe lights have been used to illuminate exits for the safety of passengers, for example as shown in U.S. Pat. No. 4,029,994-Iwans. The invention on the other hand emits light outwardly, using the aircraft or other vehicle windows themselves as the light emitting portion. Preferably, audible, visible and signalling alarms are used in combination. Although these means are provided and are cooperative with structural features of the passenger vehicle, the alarm system itself is wholly portable and self-contained, requiring absolutely no operative connection to the passenger vehicle, being entirely self-sufficient, self-powered and therefore free of possible tampering.